Hereditary Spastic Paraplegia (HSP) is a group of disorders characterized by progressive lower extremity spastic weakness. Walking is progressively impaired, wheelchairs often required, and urinary bladder disturbance and other neurologic deficits may occur. Neuropathologic studies show degeneration at the distal ends of the longest axons in the central nervous system. HSP affects an estimated 2,000 to 20,000 individuals in the United States alone. Many thousands more are at risk of inheriting this disease. The causes of HSP are largely unknown and specific treatments are not available. HSP research is proceeding rapidly. In the past five years, for example, we have learned that there are at least ten different genetic types of HSP. The gene for one form of autosomal recessive HSP was identified six months ago. Identification of the gene for the most common cause of autosomal dominant HSP is expected within the next six months. We propose to hold the first International Symposium for HSP on the campus of the University of Michigan. The Symposium Chair, Dr. John K. Fink, (Associate Professor, Dept. of Neurology, University of Michigan) has made important contributions to HSP research. Working with other HSP investigators in this country and abroad, Dr. Fink has identified two genetic loci for HSP, ascertained more than 150 HSP kindreds, and published clinical features and differential diagnosis of this disorder. An Organizing Committee has been established that includes leaders in HSP research and a patient advocate representative. This Symposium has three major objectives: 1) develop a consensus understanding of clinical, genetic, and pathologic aspects of HSP and disseminate this information to clinicians, HSP investigators, and patients; 2) develop the research tools and resources necessary for HSP research including standardized diagnostic criteria, clinical and genetic classification, functional assessment, and homogeneous cohorts of HSP patients; 3) promote collaborations between investigators. We will bring together leading investigators in clinical, genetic and pathologic aspects of HSP research. We will achieve a consensus of each aspect of HSP through a series of in-depth presentations and discussions. Following each Session, discipline-specific Writing Committees will draft consensus summaries. We will consolidate our understanding of each aspect of HSP and publish the consensus of this Symposium for medical and scientific communities. Representatives of HSP patient organizations in the United States, France, and Germany will participate in this Symposium. Working with physicians and scientists, they will prepare a summary of this Symposium in lay language for HSP patients and their families. By publicizing this Symposium, we hope to draw further attention to HSP and bring other investigators into this field. Participation of junior investigators is particularly sought. Such individuals will be invited to present abstracts during poster sessions. By consolidating and publishing information about HSP, developing research tools and shared resources, promoting collaborations, and hopefully bringing new investigators into the field, this Symposium will advance our understanding of the causes, and ultimately treatments for this group of disorders